cannot use Post requests from restsharp including headers

Question

I was like trying to make a post request using restsharp but every time I got no response...

the get request work just fine ... but every time I made a post request I ended up with no response .. here is my code :

var client = new RestClient("https://any_url_here");
        //client.Timeout = -1;
        var request = new RestRequest(Method.POST);

       // request.RequestFormat = DataFormat.Json;

       // request.AddBody(new{phoneNumber = textBox1.Text });
        request.AddParameter("phoneNumber", textBox1.Text);
        request.AddHeader("Authorization", "bcdhgyegdkj");
        request.AddHeader("Content-Type", "application/x-www-form-urlencoded");
        client.UserAgent = "Dalvik/2.1.0 (Linux; U; Android 7.1.2; S8 Build/N6F26Q)";
        request.AddHeader("Host", "any.site");
        request.AddHeader("Content-Length", "22");
        



        IRestResponse response = client.Execute(request);

        richTextBox1.Text = response.Content.ToString();

I have tried almost every way but no use ... so I have commented some lines.. also I have tried a code from postman but it did not work too.

why I did not get any response or content? I rewrite the code in python and it just worked fine.